The mechanism by which specific compounds can trigger the germination of bacterial spores is a model system to study how cells recognize and respond to chemosensory signals. In Bacillus megaterium, certain compounds such as D-glucose, L-proline, or L-perties, such as heat resistance, followed by the development of an actively growing vegetative cell from the spore. This trigger mechanism must involve some specific recognition site in the spore which then (by an unknown set of reactions) starts the process of germination. To analyze the trigger mechanism we are attempting to isolate the graphy, and binding studies. The effect of covalently modifying spore proteins to selectively alter their trigger reactions suggests that more than one specific site may exist and this observation may allow us to identify the site by selective protein modification reagents. The combined approach of chemical modification, affinity techniques, mutant analysis and other biophysical techniques using membrane probes may lead to an understanding of how the trigger mechanism functions.